View/Open

Date

2016-11-16

Author

Andersen, JCO

Cropp, A

Paradise, D

Date issued

2016-11-16

Journal

Science of the Total Environment

Type

Article

Language

en

Publisher

Elsevier

Abstract

From being a metal with very limited natural distribution, indium (In) has recently
become disseminated throughout the human society. Little is know of how In compounds
behave in the natural environment, but recent medical studies link exposure to In compounds
to elevated risk of respiratory disorders. Animal tests suggest that exposure may lead to more
widespread damage in the body, notably the liver, kidneys and spleen. In this paper, we
investigate the solubility of the most widely used In compound, indium-tin oxide (ITO) in
simulated lung and gastric fluids in order to better understand the potential pathways for
metals to be introduced into the bloodstream. Our results show significant potential for
release of In and tin (Sn) in the deep parts of the lungs (artificial lysosomal fluid) and
digestive tract, while the solubility in the upper parts of the lungs (the respiratory tract or
tracheobronchial tree) is very low.
Our study confirms that ITO is likely to remain as solid particles in the upper parts of
the lungs, but that particles are likely to slowly dissolve in the deep lungs. Considering the
prolonged residence time of inhaled particles in the deep lung, this environment is likely to
provide the major route for uptake of In and Sn from inhaled ITO nano- and microparticles.
Although dissolution through digestion may also lead to some uptake, the much shorter
residence time is likely to lead to much lower risk of uptake.

Funders/Sponsor

This paper was in part supported by the Natural Environment Research Council
(NERC, NE/L001896/1). The authors benefited from advice from and discussions with Dr
Adam Feldman, sample preparation and X-ray diffraction by Dr Gavyn Rollinson, and ICP-
MS analysis by Sharon Uren.

Description

Article

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.